This invention pertains to commercial cold tables of the type used in the food service industry. More particularly, this invention pertains to evaporator assemblies utilized for refrigerating cold tables.
Commercial cold tables are utilized in the food service industry to provide means for chilling containers of food that are exposed to ambient air from above. Commercial cold tables often comprise a refrigerated interior air chamber that is accessible by more or more hinged doors. The air chamber is typically refrigerated using an evaporator assembly. The top of the air chamber is bounded by a plurality of serving containers that can be selectively removed and replaced. Thus, while food placed in the serving containers is exposed to the ambient air, refrigerated air within the air chamber cools the serving containers and thereby chills the food in the containers. The refrigerated air chamber of a cold chamber is often also utilized to store containers of food for future use.
The safety guidelines and requirements related to the use of cold tables have changed over time and have resulted in the need to achieve lower average temperatures of the food placed in the serving containers. However, many cold tables are unable to achieve these lower temperatures due to the limitations imposed by their evaporator assemblies that refrigerate their air chambers. The evaporator assemblies utilized in older cold tables often comprised a housing, one or electric fans, and an evaporator coil. Older evaporator assemblies were typically configured such that the fans drew air into the housing of the evaporator assembly from above the evaporator coil and forced such air out of the housing in the opposite direction through the evaporator coil. To increase the ability of such evaporator assemblies to cool the exposed food containers, some evaporator assemblies have been modified by reversing the direction of the electric fan(s) such that air is drawn into the housing through the evaporator coil and is discharged from the housing by the fan(s). As result of this modification, air circulation within the air chamber is reversed and the coldest air in the air chamber is closer to the exposed serving containers, thereby allowing the cold table to achieve lower temperatures of food within the exposed serving containers.
Along with the advantages of the modified evaporator assemblies discussed above came several disadvantages. One such disadvantage is that the evaporator coil of such a modified evaporator assembly has an increased tendency to freeze-up. This is because the reversed air circulation flow direction creates a suction force on the condensation that accumulates on the convection fins of the evaporator coil. This suction force prevents the condensation from draining off evaporator coil and often results in the evaporator coil freezing-up.
Another disadvantage of the modified evaporator assemblies discussed above is that drawing air into the housing from beneath the fans has a tendency to draw debris, such as lettuce and other foods that are stored within the air chamber, into the evaporator coil. Such debris often clogs the convection fins of the evaporator coil and thereby reduces the cooling capacity of the evaporator assembly.
The present invention overcomes the above-mentioned disadvantages associated with prior art evaporator assemblies. Furthermore, the present invention enhances the efficiency of cold table evaporator assemblies by directing the coldest air within the air chamber directly toward the exposed serving containers.